Triple-stranded DNA (also known as H-DNA or Triplex-DNA) is a DNA structure in which three oligonucleotides wind around each other and form a triple helix. In triple-stranded DNA, the third strand binds to a B-form DNA (via Watson–Crick base-pairing) double helix by forming Hoogsteen base pairs or reversed Hoogsteen hydrogen bonds.
But do you know? Another form of DNA- the triplex helix DNA or three-stranded DNA structure also exists in nature. Triple helix DNA forms when a single-stranded DNA binds with the double-stranded DNA. So what a triplex helix DNA is, how does it form and what is its biological significance? Let’s find out.
What is Triple Helix DNA and How Does it Form? - Genetic Education
A triple helix DNA structure would introduce significant challenges for fundamental genetic processes. DNA replication, the copying of the entire genome before cell division, would face hurdles.
The use of TFO is limited to the presence of oligopyrimidine oligopurine sequences in the DNA target and by the stability of the triple-helical structure. However, triple-helix target sites (TTS) are over-represented in the human genome and especially at promoter regions (12, 13).
Occasionally, DNA even comes in the form of a triple helix! In this rare genetic structure, the third strand winds around the central double helix in the larger spaces left by the original staircase shape.
Triple-stranded DNA (also known as H-DNA or Triplex-DNA) is a DNA structure in which three oligonucleotides wind around each other and form a triple helix. In triple-stranded DNA, the third strand binds to a B-form DNA (via Watson–Crick base-pairing) double helix by forming Hoogsteen base pair s or reversed Hoogsteen hydrogen bonds.